Configuration of the DNS client.

DNS Client Configuration File

The DNS client configuration file Net_Config_DNS_Client.h contains only the setting Cache Table Size which specifies the size of the DNS Cache by defining the number of entries for the DNS Cache table. When the IP address is resolved, it is also stored to the local cache. When a request for resolving an IP address is received, the DNS Client first checks the local cache memory. If a valid entry is found there, the IP address is taken from the cache, and the request is not sent on to the remote DNS Server.

Note: DNS Cache entries expire after a Time to Live (TTL) timeout. This is defined by the DNS Server. The TTL value for resolved IP addresses is received in an answer packet from the DNS Server. The DNS Client manages the timeouts. When a timeout counter expires, the DNS Cache entry is deleted from the Cache.